Odds of Getting In
Have you heard the story about how Bill Gates quit Harvard to found Microsoft? As a computer scientist, he is a type of mathematician (and he's absolutely one of the most successful). Unfortunately, the only reason you know this story is because it's so crazy unlikely to happen that it has become a legend. It's like Washington crossing the Delaware...or Davy Crockett, king of the wild frontier.
The safer way to go about it would be to actually finish school, and then go do more school and finish that too. Once you get that done, your odds of getting in will actually be pretty good. Just about every employer, from NASA to Google to the next big robot company will want you to have an advanced degree. So if you really, truly want to use that big brain of yours to figure out how we build the machine servants of the future, you're going to have to fill it to the brim.